Magnetic filters are known in the art and developments in the art continue in light of industry needs and demands. Most prior art spin-on magnetic filters are less than satisfactory in their performance in that the location of the magnetic filtration means is typically downstream from the filter media and/or not directly in the fluid flow. Furthermore, the great majority of prior art filter elements having magnetic filtering capabilities are not of the spin-on type, and thus a significant portion of the present day filter market has not been directly developed with respect to magnetic filtration.
The present invention is directed particularly to spin-on fluid filter elements. The need for magnetic filtration is especially critical in the areas in which spin-on fluid filters are used in that stray ferrous particles can do significant damage to a fluid circuit, e.g. a hydraulic circuit, and they can also damage the finer filter media thereby compromising the overall filtering capacity of the element. Thus, not only is there the problem of providing magnetic filtration in a spin-on fluid filter assembly, but there is also the problem of achieving such filtration before the magnetic particles reach the filter media. The present invention accomplishes these objectives in a manner which is commercially feasible and universally applicable to virtually all types of spin-on fluid filter elements.